Gene expression profile of bladder tissue of patients with ulcerative interstitial cystitis

Gut microbiota and interstitial cystitis: exploring the gut-bladder axis through mendelian randomization, biological annotation and bulk RNA sequencing

Background

Several observational studies have indicated an association between interstitial cystitis and the composition of the gut microbiota; however, the causality and underlying mechanisms remain unclear. Understanding the link between gut microbiota and interstitial cystitis could inform strategies for prevention and treatment.

Methods

A two-sample Mendelian randomization analysis was conducted using published genome-wide association study summary statistics. We employed inverse variance weighted, weighted mode, MR-Egger, weighted median, simple mode, and cML-MA methods to investigate the causal relationship between gut microbiota and interstitial cystitis. Sensitivity analysis was performed to validate the results. Relevant gut microbiota was examined through reverse MR. Single nucleotide polymorphisms were annotated using FUMA to identify genes associated with these genetic variants, thereby revealing potential host gene-microbiota associations in interstitial cystitis patients.

Results

Eight bacterial taxa were identified in our analysis as associated with interstitial cystitis. Among these, Butyricimonas, Coprococcus, Lactobacillales, Lentisphaerae, and Bilophila wadsworthia were positively correlated with interstitial cystitis risk, while taxa such as Desulfovibrio piger, Oscillibacter unclassified and Ruminococcus lactaris exhibited protective effects against interstitial cystitis. The robustness of these associations was confirmed through sensitivity analyses. Reverse MR analysis did not reveal evidence of reverse causality. Single nucleotide polymorphisms were annotated using FUMA and subjected to biological analysis. Seven hub genes (SPTBN1, PSME4, CHAC2, ERLEC1, ASB3, STAT5A, and STAT3) were identified as differentially expressed between interstitial cystitis patients and healthy individuals, representing potential therapeutic targets.

Conclusion

Our two-sample Mendelian randomization study established a causal relationship between gut microbiota and interstitial cystitis. Furthermore, our identification of a host gene-microbiota association offers a new avenue for investigating the potential pathogenesis of interstitial cystitis and suggests avenues for the development of personalized treatment strategies.

An integrated machine learning framework for developing and validating a diagnostic model of major depressive disorder based on interstitial cystitis-related genes

BACKGROUND

Major depressive disorder (MDD) and interstitial cystitis (IC) are two highly debilitating conditions that often coexist with reciprocal effect, significantly exacerbating patients' suffering. However, the molecular underpinnings linking these disorders remain poorly understood.

METHODS

Transcriptomic data from GEO datasets including those of MDD and IC patients was systematically analyzed to develop and validate our model. Following removal of batch effect, differentially expressed genes (DEGs) between respective disease and control groups were identified. Shared DEGs of the conditions then underwent functional enrichment analyses. Additionally, immune infiltration analysis was quantified through ssGSEA. A diagnostic model for MDD was constructed by exploring 113 combinations of 12 machine learning algorithms with 10-fold cross-validation on the training sets following by external validation on test sets. Finally, the "Enrichr" platform was utilized to identify potential drugs for MDD.

RESULTS

Totally, 21 key genes closely associated with both MDD and IC were identified, predominantly involved in immune processes based on enrichment analyses. Immune infiltration analysis revealed distinct profiles of immune cell infiltration in MDD and IC compared to healthy controls. From these genes, a robust 11-gene (ABCD2, ATP8B4, TNNT1, AKR1C3, SLC26A8, S100A12, PTX3, FAM3B, ITGA2B, OLFM4, BCL7A) diagnostic signature was constructed, which exhibited superior performance over existing MDD diagnostic models both in training and testing cohorts. Additionally, epigallocatechin gallate and 10 other drugs emerged as potential targets for MDD.

CONCLUSION

Our work developed a diagnostic model for MDD employing a combination of bioinformatic techniques and machine learning methods, focusing on shared genes between MDD and IC.

Bioinformatics in urology - molecular characterization of pathophysiology and response to treatment

The application of bioinformatics has revolutionized the practice of medicine in the past 20 years. From early studies that uncovered subtypes of cancer to broad efforts spearheaded by the Cancer Genome Atlas initiative, the use of bioinformatics strategies to analyse high-dimensional data has provided unprecedented insights into the molecular basis of disease. In addition to the identification of disease subtypes - which enables risk stratification - informatics analysis has facilitated the identification of novel risk factors and drivers of disease, biomarkers of progression and treatment response, as well as possibilities for drug repurposing or repositioning; moreover, bioinformatics has guided research towards precision and personalized medicine. Implementation of specific computational approaches such as artificial intelligence, machine learning and molecular subtyping has yet to become widespread in urology clinical practice for reasons of cost, disruption of clinical workflow and need for prospective validation of informatics approaches in independent patient cohorts. Solving these challenges might accelerate routine integration of bioinformatics into clinical settings.

Potential Role of Macrophage Polarization in the Progression of Hunner-Type Interstitial Cystitis

BACKGROUND

Hunner-type interstitial cystitis (HIC) is a chronic inflammatory condition of the bladder. However, it remains unclear whether there is a causal relationship between the presence of Hunner lesions and seemingly normal-appearing areas in the bladder (non-Hunner lesions). This study aimed to investigate the fundamental aspects of HIC by examining potential genetic differences between Hunner and non-Hunner lesions and elucidate their role as potential markers in the progression and suppression of the disease.

METHODS

This cross-sectional study enrolled patients with HIC (n = 10) who underwent supratrigonal cystectomy along with augmentation cystoplasty. Full-thickness bladder tissue was collected from Hunner and non-Hunner lesions in the same patient. Normal bladder tissue biopsies were also obtained as controls. Whole transcriptome analysis was performed to analyze the gene expression patterns and immune cell populations.

RESULTS

The mucosal layers of patients exhibited similar pathway dysregulation across Hunner and non-Hunner lesions, with immunerelated pathways being prominently affected. In the mucosal layer, genes related to anti-inflammatory and immune suppression were downregulated in Hunner lesions compared to non-Hunner lesions. Moreover, in Hunner lesions, genes related to macrophage differentiation and polarization, such as VSIG4, CD68, MAFB, and LIRB4, were downregulated. The cell fraction of M2 macrophages was found to decrease in Hunner lesions. Immunohistochemical staining revealed an elevated fraction of M1 macrophages and a reduced fraction of M2 macrophages in Hunner lesions compared to those in non-Hunner lesions. In the muscular layer, transcriptomic evidence of muscle thickness was observed in both Hunner and non-Hunner lesions; however, the difference was not significant.

CONCLUSION

Hunner lesions showed a reduced expression of anti-inflammatory and immunosuppressive factors compared to non-Hunner lesions, along with alterations in immune cell populations. This study suggests the possibility that macrophage polarization is related to the progression from non-Hunner lesions to Hunner lesions, suggesting its relevance to the characteristics of autoimmune diseases.

Genome-wide association study identifies risk loci within the major histocompatibility complex region for Hunner-type interstitial cystitis

Hunner-type interstitial cystitis (HIC) is a rare, chronic inflammatory disease of the urinary bladder with unknown etiology and genetic background. Here, we conduct a genome-wide association study of 144 patients with HIC and 41,516 controls of Japanese ancestry. The genetic variant, rs1794275, in the major histocompatibility complex (MHC) region (chromosome 6p21.3) is associated with HIC risk (odds ratio [OR] = 2.32; p = 3.4 × 10^-9). The association is confirmed in a replication set of 26 cases and 1,026 controls (p = 0.014). Fine mapping demonstrates the contribution to the disease risk of a completely linked haplotype of three human leukocyte antigen HLA-DQβ1 amino acid positions, 71, 74, and 75 (OR = 1.94; p = 5 × 10^-8) and of HLA-DPβ1 amino acid position 178, which tags HLA-DPB1∗04:02 (OR = 2.35; p = 7.5 × 10^-8). The three HLA-DQβ1 amino acid positions are located together at the peptide binding groove, suggesting their functional importance in antigen presentation. Our study reveals genetic contributions to HIC risk that may be associated with class II MHC molecule antigen presentation.

Multimodal Single-Cell Analyses Outline the Immune Microenvironment and Therapeutic Effectors of Interstitial Cystitis/Bladder Pain Syndrome

Interstitial cystitis/bladder pain syndrome (IC/BPS) has a significant impact on quality of life, but the etiopathogenesis remains largely unknown. The bladder microenvironment of patients with IC/BPS to obtain biological evidence supporting diagnosis and novel therapy is systematically characterized. Single-cell RNA sequencing (scRNA-seq) and image mass cytometry (IMC) are applied to bladder biopsies of the IC/BPS cohort. A total of 42 distinct cell clusters are identified from different groups. The increased hyperactivated Th1-biased response, but not Th2-biased response, and decreased immunosuppressive Treg are elucidated in the bladder microenvironment of non-Hunner-type IC (NHIC)/Hunner-type IC (HIC). M2/M2-like macrophage extends in the HIC and M1-like macrophage extends in NHIC, all of which secrete a range of chemokines with different pattern. The pro-inflammatory mediators, TNF-α, produced by tissue-resident macrophages and IL6, by the inflammatory fibroblasts are identified as key mediators of IC/BPS pathogenesis. Additionally, a regulatory network between different cell types is observed as a shift from structural cell communication in unaffected normal bladder to a Macrophage-Endothelial-dominated interactome in NHIC/HIC. The results demonstrate the high heterogeneity in NHIC/HIC, and provide an essential resource for diagnosis, and treatment of IC/BPS in the future by highlighting the importance of the microenvironment of bladder mucosa.

Integrating single-cell RNA sequencing with spatial transcriptomics reveals immune landscape for interstitial cystitis

Interstitial cystitis (IC) is a severely debilitating and chronic disorder with unclear etiology and pathophysiology, which makes the diagnosis difficult and treatment challenging. To investigate the role of immunity in IC bladders, we sequenced 135,091 CD45⁺ immune cells from 15 female patients with IC and 9 controls with stress urinary incontinence using single-cell RNA sequencing (scRNA-seq). 22 immune subpopulations were identified in the constructed landscape. Among them, M2-like macrophages, inflammatory CD14⁺ macrophages, and conventional dendritic cells had the most communications with other immune cells. Then, a significant increase of central memory CD4⁺ T cells, regulatory T cells, GZMK⁺CD8⁺ T cells, activated B cells, un-switched memory B cells, and neutrophils, and a significant decrease of CD8⁺ effector T cells, Th17 cells, follicular helper T cells, switched memory B cells, transitional B cells, and macrophages were noted in IC bladders. The enrichment analysis identified a virus-related response during the dynamic change of cell proportion, furthermore, the human polyomavirus-2 was detected with a positive rate of 95% in urine of patients with IC. By integrating the results of scRNA-seq with spatial transcriptomics, we found nearly all immune subpopulations were enriched in the urothelial region or located close to fibroblasts in IC bladders, but they were discovered around urothelium and smooth muscle cells in control bladders. These findings depict the immune landscape for IC and might provide valuable insights into the pathophysiology of IC.

Activation of CXCL13/CXCR5 axis aggravates experimental autoimmune cystitis and interstitial cystitis/bladder pain syndrome

The abnormal CXCL13/CXCR5 axis is involved in many inflammatory diseases and its selective inhibitor, TAK-799 has exhibited strong anti-inflammatory potency. The sequencing of clinical specimens from interstitial cystitis/bladder pain syndrome (IC/BPS) has shown that CXCL13 and CXCR5 are highly expressed, but the role of CXCL13/CXCR5 axis in IC/BPS has not been rarely reported. Therefore, in this study, we analyzed the GSE11783 sequencing data of IC/BPS patients and investigate the role and mechanism of CXCL13/CXCR5 axis and TAK-779 in the mouse model of experimental autoimmune cystitis (EAC). We verified that CXCL13 and CXCR5 were significantly up-regulated in EAC model. EAC mice exhibited increased bladder inflammatory factors (IL-6, TNF-α, IL-1β), apoptosis-related proteins (Bax, Caspase-3, Caspase-8), frequency of voiding. Using TAK779 to block CXCL13/CXCR5 axis significantly attenuated these inflammatory damages and efficiently improved bladder function (significant reduction in micturition frequency, significant prolongation of inter-contraction interval). Further investigation showed that inhibiton of JNK and NF-kappaB activation, the bioinformatics analysis-indicated downstream signaling of CXCL13/CXCR5 axis, is responsible for the protective effect of TAK779. Taken together, we demonstrate that activation of the CXCL13/CXCR5 axis is involved in the pathophysiology of IC/BPS and EAC. Blocking CXCL13/CXCR5 axis activation by TAK-779 reduces bladder inflammation and improves bladder function in EAC mice.

Defining Molecular Treatment Targets for Bladder Pain Syndrome/Interstitial Cystitis: Uncovering Adhesion Molecules

Bladder pain syndrome/interstitial cystitis (BPS/IC) is a debilitating pain syndrome of unknown etiology that predominantly affects females. Clinically, BPS/IC presents in a wide spectrum where all patients report severe bladder pain together with one or more urinary tract symptoms. On bladder examination, some have normal-appearing bladders on cystoscopy, whereas others may have severely inflamed bladder walls with easily bleeding areas (glomerulations) and ulcerations (Hunner’s lesion). Thus, the reported prevalence of BPS/IC is also highly variable, between 0.06% and 30%. Nevertheless, it is rightly defined as a rare disease (ORPHA:37202). The aetiopathogenesis of BPS/IC remains largely unknown. Current treatment is mainly symptomatic and palliative, which certainly adds to the suffering of patients. BPS/IC is known to have a genetic component. However, the genes responsible are not defined yet. In addition to traditional genetic approaches, novel research methodologies involving bioinformatics are evaluated to elucidate the genetic basis of BPS/IC. This article aims to review the current evidence on the genetic basis of BPS/IC to determine the most promising targets for possible novel treatments.

WGCNA and molecular docking reveal key hub genes and potential natural inhibitor in interstitial cystitis/bladder pain syndrome

INTRODUCTION AND HYPOTHESIS

The etiology and treatment of interstitial cystitis/bladder pain syndrome are still controversial. The purpose of this study is to determine the key genes and specific regulatory pathways related to it and to find potential drug-active components through integrated bioinformatics.

METHODS

The data set GSE11783 was downloaded from GEO database. The modules significantly related to interstitial cystitis/bladder pain syndrome were identified by weighted correlation network analysis. The genes in the key modules were analyzed by functional enrichment and protein interaction by Cytoscape software, and finally the core hub genes were screened. Furthermore, the molecular docking verification of active components and key proteins was carried out by using AutoDock Vin software.

RESULTS

Among the 14 modules derived from WGCNA, turquoise module had the highest correlation with IC/BPS (r = 0.85, P < 0.001). The genes in the module were mainly enriched in the biological processes such as the interaction between cytokines and cytokine receptors and chemokine signaling pathway. The genes in the related modules of differentially expressed genes and WGCNA traits were intersected to obtain the core hub genes. Protein-protein interaction network analysis showed that the key genes were upregulated genes CCR7 and CCL19. In terms of molecular docking, triptolide, the active component in the traditional anti-inflammatory drug Tripterygium wilfordii, can form effective molecular binding with both core hub genes.

CONCLUSIONS

Our study identified the core hub genes CCR7 and CCL19, which acted as essential components in interstitial cystitis/bladder pain syndrome. Furthermore, CCR7 and CCL19 can form effective binding with triptolide, which will provide new insights into the development of new therapies for interstitial cystitis/bladder pain syndrome.

Emerging molecular mechanisms and genetic targets for developing novel therapeutic strategies for treating bladder diseases

Bladder diseases affect millions of patients worldwide and compromise their quality of life with a substantial economic impact. The not fully understood aetiologies of bladder diseases limit the current diagnosis and therapeutic options to primarily symptomatic treatment. In addition, bladder targeted drug delivery is challenging due to its unique anatomical features and its natural physiological function of urine storage and frequent voiding. Therefore, current treatment options often fail to provide a highly effective, precisely targeted and long-lasting treatment. With the growing maturity of gene therapy, comprehensive studies are needed to provide a better understanding of the molecular mechanisms underpinning bladder diseases and help to identify novel gene therapeutic targets and biomarkers for treating bladder diseases. In this review, molecular mechanisms involved in pathology of bladder cancer, interstitial cystitis and overactive bladder syndrome are reviewed, with focus on establishing potential novel treatment options. Proposed novel therapies, including gene therapy combined with nanotechnology, localised drug delivery by nanoparticles, and probiotics, are discussed in regard to their safety profiles, efficacy, treatment lenght, precise targeting, and in comparison to conventional treatment methods.

Integrated Analysis of Microarray Studies to Identify Novel Diagnostic Markers in Bladder Pain Syndrome/Interstitial Cystitis with Hunner Lesion

Background

The aim of this study was to identify novel genetic features of Hunner’s lesion interstitial cystitis (HIC) via comprehensive analysis of the Gene Expression Omnibus (GEO) database.

Methods

The GSE11783 and GSE28242 datasets were downloaded from GEO for further analysis. Differentially expressed genes (DEGs) were identified and analyzed for functional annotation. The diagnostic markers for HIC were screened and validated using the least absolute shrinkage and selection operator (LASSO) logistic regression and support vector machine recursive feature elimination (SVM-RFE) algorithms. Finally, the cell-type identification by estimating relative subsets of RNA transcripts (CIBERSORT) algorithm was adopted to investigate the correlation between immune cell infiltration and diagnostic markers in HIC.

Results

A total of 7837 DEGs were identified in GSE11783 and 1583 DEGs in GSE28242. Venn diagrams were used to obtain 16 overlapping upregulated and 67 overlapping downregulated DEGs separately. The LASSO logistic model and SVM-RFE algorithm were used to identify 6 genes including KRT20, SLFN11, CD86, ITGA4, PLAC8, and BTN3A3 from DEGs as diagnostic markers for HIC. Their diagnostic potential in HIC and bladder pain syndrome/interstitial cystitis (BPS/IC) were acceptable. PLAC8 exhibited the best diagnostic performance in BPS/IC with an area under the curve of 0.916. The results of immune infiltration involving GSE11783 revealed that the plasma cell ratio (p = 0.017), activated memory CD4+ T cells (p = 0.009), activated dendritic cells (p = 0.01), eosinophils (p = 0.004), and neutrophils (p = 0.03) were significantly higher in HIC than in normal samples, in contrast to resting mast cells (p = 0.022). A positive correlation existed between diagnostic markers and infiltrating immune cells.

Conclusion

KRT20, SLFN11, CD86, ITGA4, PLAC8, and BTN3A3 represent novel and potent diagnostic markers for HIC. They also exhibit certain diagnostic potential in BPS/IC. Immune cell infiltration might play a key role in the pathogenesis and progression of BPS/IC.

[Interstitial cystitis: the latest findings on its aetiopathogenesis]

New findings provide progress in the understanding of the complicated aetiopathogenesis of interstitial cystitis/bladder pain syndrome (IC/BPS), whose causalities have only been deciphered in fragments so far. An increasingly complex network of pathomechanisms is emerging, in which the frequently mentioned mast cells and urothelial changes seem to be only a fragment of the pathological changes. The latest findings regarding a possible genetic and epigenetic predisposition are based on pedigree analyses, detection of single nucleotide polymorphisms and significant changes in differentially expressed genes. Multiple alterations can be detected at the molecular level. Platelet-activating factor, VEGF, corticotropin-releasing hormone and the inflammasome are important players in understanding the disease, but the pathomechanism underlying the "activation" of IC remains unclear. New starting points could be the detection of viruses (Epstein-Barr virus, BK polyomaviruses) or bacterial inflammation by pathogens that cannot be detected in standard cultures.

Biomarkers in the Light of the Etiopathology of IC/BPS

In this review, we focused on putatively interesting biomarkers of interstitial cystitis/bladder pain syndrome (IC/BPS) in relation to the etiopathology of this disease. Since its etiopathology is still under discussion, the development of novel biomarkers is critical for the correct classification of the patients in order to open personalized treatment options, on the one hand, and to separate true IC/BPS from the numerous confusable diseases with comparable symptom spectra on the other hand. There is growing evidence supporting the notion that the classical or Hunner-type IC (HIC) and the non-Hunner-type IC (NHIC) are different diseases with different etiopathologies and different pathophysiology at the full-blown state. While genetic alterations indicate close relationship to allergic and autoimmune diseases, at present, the genetic origin of IC/BPS could be identified. Disturbed angiogenesis and impairment of the microvessels could be linked to altered humoral signaling cascades leading to enhanced VEGF levels which in turn could enhance leucocyte and mast cell invasion. Recurrent or chronic urinary tract infection has been speculated to promote IC/BPS. New findings show that occult virus infections occurred in most IC/BPS patients and that the urinary microbiome was altered, supporting the hypothesis of infections as major players in IC/BPS. Environmental and nutritional factors may also influence IC/BPS, at least at a late state (e.g., cigarette smoking can enhance IC/BPS symptoms). The damage of the urothelial barrier could possibly be the result of many different causality chains and mark the final state of IC/BPS, the causes of this development having been introduced years ago. We conclude that the etiopathology of IC/BPS is complex, involving regulatory mechanisms at various levels. However, using novel molecular biologic techniques promise more sophisticated analysis of this pathophysiological network, resulting in a constantly improvement of our understanding of IC/BPS and related diseases.

Identification of novel biomarkers in Hunner's interstitial cystitis using the CIBERSORT, an algorithm based on machine learning

Background

 Hunner’s interstitial cystitis (HIC) is a complex disorder characterized by pelvic pain, disrupted urine storage, and Hunner lesions seen on cystoscopy. There are few effective diagnostic biomarkers. In the present study, we used the novel machine learning tool CIBERSORT to measure immune cell subset infiltration and potential novel diagnostic biomarkers for HIC.

Methods

The GSE11783 and GSE57560 datasets were downloaded from the Gene Expression Omnibus for analysis. Ten HIC and six healthy samples from GSE11783 were analyzed using the CIBERSORT algorithm. Gene Set Enrichment Analysis (GSEA) was performed to identify biological processes that occur during HIC pathogenesis. Finally, expression levels of 11 T cell follicular helper cell (Tfh) markers were compared between three healthy individuals and four patients from GSE57560.

Results

Six types of immune cells in HIC from GSE11783 showed significant differences, including resting mast cells, CD4⁺ memory-activated T cells (CD3⁺ CD4⁺ HLA-DR⁺ cells), M0 and M2 macrophages, Tfh cells, and activated natural killer cells. Except for plasma cells, there were no significant differences between Hunner’s lesion and non-Hunner’s lesion areas in HIC. The GSEA revealed significantly altered biological processes, including antigen–antibody reactions, autoimmune diseases, and infections of viruses, bacteria, and parasites. There were 11 Tfh cell markers with elevated expression in patients from GSE57560.

Conclusion

This was the first demonstration of Tfh cells and CD3⁺ CD4⁺ HLA-DR⁺ cells with elevated expression in HIC. These cells might serve as novel diagnostic biomarkers.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12894-021-00875-8.

Exploration of the core genes in ulcerative interstitial cystitis/bladder pain syndrome

Objective:

Interstitial cystitis (IC)/bladder pain syndrome (BPS) is a chronic inflammatory disease that can cause bladder pain and accompanying symptoms, such as long-term urinary frequency and urgency. IC/BPS can be ulcerative or non-ulcerative. The aim of this study was to explore the core genes involved in the pathogenesis of ulcerative IC, and thus the potential biomarkers for clinical treatment.

Materials and Methods:

First, the gene expression dataset GSE11783 was downloaded using the Gene Expression Omnibus (GEO) database and analyzed using the limma package in R to identify differentially expressed genes (DEGs). Then, the Database for Annotation, Visualization and Integrated Discovery (DAVID) was used for Gene Ontology (GO) functional analysis, and the Kyoto Encyclopedia of Genes and Genomes (KEGG) was used for pathway enrichment analysis. Finally, the protein-protein interaction (PPI) network was constructed, and key modules and hub genes were determined using the STRING and Cytoscape software. The resulting key modules were then analyzed for tissue-specific gene expression using BioGPS.

Results:

A total of 216 up-regulated DEGs and 267 down-regulated genes were identified, and three key modules and nine hub genes were obtained.

Conclusion:

The core genes (CXCL8, CXCL1, IL6) obtained in this study may be potential biomarkers of interstitial cystitis with guiding significance for clinical treatment.

AOAH remodels arachidonic acid-containing phospholipid pools in a model of interstitial cystitis pain: A MAPP Network study

Interstitial cystitis/bladder pain syndrome (IC) is a debilitating condition of chronic pelvic pain with unknown etiology. Recently, we used a genetic approach in a murine model of IC to identify the lipase acyloxyacyl hydrolase (AOAH) as a modulator of pelvic pain. We found that AOAH-deficient mice have elevated pelvic pain responses, and AOAH immunoreactivity was detected along the bladder-brain axis. Lipidomic analyses identified arachidonic acid (AA) and its metabolite PGE₂ as significantly elevated in the sacral spinal cord of AOAH-deficient mice, suggesting AA is a substrate for AOAH. Here, we quantified the effects of AOAH on phospholipids containing AA. Spinal cord lipidomics revealed increased AA-containing phosphatidylcholine in AOAH-deficient mice and concomitantly decreased AA-phosphatidylethanolamine, consistent with decreased CoA-independent transferase activity (CoIT). Overexpression of AOAH in cell cultures similarly altered distribution of AA in phospholipid pools, promoted AA incorporation, and resulted in decreased membrane fluidity. Finally, administration of a PGE₂ receptor antagonist reduced pelvic pain in AOAH-deficient mice. Together, these findings suggest that AOAH represents a potential CoA-independent AA transferase that modulates CNS pain pathways at the level of phospholipid metabolism.

Interstitial cystitis, bladder pain syndrome, hypersensitive bladder, and interstitial cystitis/bladder pain syndrome - clarification of definitions and relationships

Interstitial cystitis and interstitial cystitis-related conditions such as bladder pain syndrome and hypersensitive bladder have a similar symptomatic profile but probably different etiologies. A meaningful classification of these diseases/conditions is mandatory for clinical and investigational progress. The condition with Hunner lesions (Hunner type interstitial cystitis) is distinct from other categories in terms of histopathology, gene expression, and clinical management. Classification should clearly differentiate the presence or absence of Hunner lesions. The term covering patients as a whole should contain interstitial cystitis, since interstitial cystitis is historically a well-known name and used for insurance reimbursement. The proposed taxonomy features an umbrella term (interstitial cystitis/bladder pain syndrome) and two subgroups, Hunner type interstitial cystitis (with Hunner lesions) and bladder pain syndrome (without Hunner lesions). Interstitial cystitis/bladder pain syndrome is convenient for initial management, and subgroups can categorize the patients for specific management. The characteristic symptom profile is to be collectively termed as hypersensitive bladder symptoms.

Bioinformatics Approach for Identifying Novel Biomarkers and Their Signaling Pathways Involved in Interstitial Cystitis/Bladder Pain Syndrome with Hunner Lesion

The complexity of interstitial cystitis/bladder pain syndrome (IC/BPS) has led to considerable uncertainty in terms of diagnosis and prevalence of the condition. Here, we try to identify the IC/BPS-associated genes through an integrated analysis of Gene Expression Omnibus (GEO) datasets and confirm experimentally to predict the pathologic diagnosis of IC/BPS. Data mining analysis of GEO datasets (GSE621, GSE11783, GSE28242, and GSE57560) revealed a total of 53 (51 upregulated and two downregulated) common differentially expressed genes (DEGs) in IC/BPS. A protein–protein interaction (PPI) network was then constructed with the 53 common DEGs using Cytoscape v3.7.2, and subsequently, six hub genes (CD5, CD38, ITGAL, IL7R, KLRB1, and IL7R) were identified using cytoHubba v0.1 that were upregulated in IC/BPS. Enrichment analysis of common DEGs revealed that hematopoietic cell lineage, immune system, and T-cell receptor (TCR) signaling in naïve CD4+ T cell signaling pathways were prominently involved with the common 51 upregulated DEGs. The two common downregulated DEGs may enrich linoleic acid metabolism and synthesis of epoxy (EET) and dihydroxyeicosatrienoic acid (DHET) signaling pathways in IC/BPS. Moreover, our RT-PCR data confirmed that the expression of the five hub genes (CD38, ITGAL, IL7R, KLRB1, and IL7R) was significantly augmented in IC/BPS patients’ samples when compared with their normal counterparts. In this study, we systematically predict the significant biomarkers and possible signaling pathways involved in IC/BPS, confirming the differential expression of the hub genes in tissue samples from patients with IC/BPS. Thus, the hub genes might be used as potential diagnostic biomarkers of IC/BPS.

Notch controls urothelial integrity in the mouse bladder

The Notch signaling pathway mediates cell-cell communication regulating cell differentiation and proliferation and cell fate decisions in various tissues. In the urinary bladder, Notch acts as a tumor suppressor in mice, while mutations in Notch pathway components have been identified in human bladder cancer as well. Here we report that the genetic inactivation of Notch in mice leads to downregulation of cell-cell and cell-ECM interaction components, including proteins previously implicated in interstitial cystitis/bladder pain syndrome (IC/BPS), structural defects and mucosal sloughing, inflammation, and leaky urine-blood barrier. Molecular profiling of ailing mouse bladders showed similarities with IC/BPS patient tissue, which also presented low Notch pathway activity as indicated by reduced expression of canonical Notch targets. Urothelial integrity was reconstituted upon exogenous reactivation of the Notch pathway, implying a direct involvement of Notch. Despite damage and inflammation, urothelial cells failed to proliferate, uncovering a possible role for α4 integrin in urothelial homeostasis. Our data uncover a broad role for Notch in bladder homeostasis involving urothelial cell crosstalk with the microenvironment.

Urinary microbiome in uncomplicated and interstitial cystitis: is there any similarity?

PURPOSE

Acute/uncomplicated cystitis is the most common bacterial infection causing inflammation in the bladder tissues and predominantly diagnosed in women. Interstitial cystitis may too, cause inflammation in the bladder but its etiology has been elusive. Even though the site and symptoms of both diseases are largely shared, state of the urinary microbiome in these disorders have not been comparatively evaluated before. The purpose of this review is to assess and qualitatively compare structure and composition of the urinary microbiome in acute/uncomplicated cystitis and interstitial cystitis.

METHODS AND RESULTS

The available literature in MEDLINE are extensively searched using keywords and screened. Pertinent evidence is carefully assessed and synthesized. We included the original studies with a cohort of medically stable, non-pregnant women with otherwise functionally normal urinary tract and excluded the original articles if the infection in a patient's cohort is accompanied by urinary syndromes such as incontinence and overactive bladder syndrome. A total of six original papers reporting on the urinary microbiome in acute cystitis and nine papers on the interstitial cystitis met the selection criteria.

CONCLUSION

The evidence we have gleaned from the literature on the urinary microbiome associated with the acute and interstitial cystitis does not point to convergence of microbiome similarities between the two diseases. More studies with direct sampling of the bladder tissues besides sampling bladder surfaces are warranted for accurate comparison of microbiome similarity between the two conditions. The future research on interstitial cystitis microbiome should include stratified cohorts with prospective design.

Systematic screening of protein-coding gene expression identified HMMR as a potential independent indicator of unfavorable survival in patients with papillary muscle-invasive bladder cancer

Papillary and non-papillary are two histological patterns of bladder carcinogenesis and are considered as dual-track oncogenic pathways, which have different genetic alterations. The TCGA-bladder cancer (BLCA) database contains clinicopathological, genomic and survival data from over 400 muscle-invasive bladder cancer patients. In this study, using data from this database, we performed a systematic screening of gene expression to identify the protein-coding gene that might have prognostic value in papillary and non-papillary muscle-invasive bladder cancer (MIBC). The data of patients with primary MIBC in TCGA-BLCA was acquired from the UCSC Xena project (http://xena.ucsc.edu) for re-analysis. By setting |log2 fold change|≥2 and adjusted p value <0.01 as the screening criteria, we found 751 significantly dysregulated genes, including 183 overexpressed and 568 downregulated genes. HMMR was identified as a potential prognostic marker with unique expression. Multivariate analysis showed that its expression was an independent prognostic indicator of shorter progression-free survival (PFS) (HR: 1.400, 95%CI: 1.021-1.920, p = 0.037) in the papillary subtype. ENST00000393915.8 and ENST00000358715.3, two transcripts that contain all 18 exons and encode the full length of HMMR, were significantly upregulated in cancer tissues compared with normal bladder tissues. None of the 17 CpG sites in its DNA locus was relevant to HMMR expression. 26/403 (6.5%) MIBC cases had HMMR gene-level amplification, which was associated with upregulated HMMR expression compared with the copy-neutral and deletion groups. Gene set enrichment analysis (GSEA) in papillary MIBC found that the high HMMR expression group was associated with upregulated genes enriched in multiple gene sets with well-established role in BC development, including G2M checkpoint, E2 F Targets, Myc Targets V1, Myc Targets V2 and Glycolysis. Based on these findings, we infer that HMMR expression might be a specific prognostic marker in terms of PFS in papillary MIBC. DNA amplification might be an important mechanism of its elevation.

Purinergic P2X7 receptors as therapeutic targets in interstitial cystitis/bladder pain syndrome; key role of ATP signaling in inflammation

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic lower urinary tract condition. Patients with IC/BPS suffer from debilitating pain and urinary urgency. The underlying etiology of IC/BPS is unknown and as such current treatments are mostly symptomatic with no real cure. Many theories have been proposed to describe the etiology of IC/BPS, but this review focuses on the role of inflammation. In IC/BPS patients, the permeability of the urothelium barrier is compromised and inflammatory cells infiltrate the bladder wall. There are increased levels of many inflammatory mediators in patients with IC/BPS and symptoms such as pain and urgency that have been associated with the degree of inflammation. Recent evidence has highlighted the role of purinergic receptors, specifically the P2X7 receptor, in the process of inflammation. The results from studies in animals including cyclophosphamide-induced hemorrhagic cystitis strongly support the role of P2X7 receptors in inflammation. Furthermore, the deletion of the P2X7 receptor or antagonism of this receptor significantly reduces inflammatory mediator release from the bladder and improves symptoms. Research results from IC/BPS patients and animal models of IC/BPS strongly support the crucial role of inflammation in the pathophysiology of this painful disease. Purinergic signaling and purinergic receptors, especially the P2X7 receptor, play an undisputed role in inflammation. Purinergic receptor antagonists show positive results in treating different symptoms of IC/BPS.

Bioinformatics-based discovery of the urinary BBOX1 mRNA as a potential biomarker of diabetic kidney disease

Background

Diabetic kidney disease (DKD) is the leading cause of end-stage kidney disease (ESKD) in the world. Emerging evidence has shown that urinary mRNAs may serve as early diagnostic and prognostic biomarkers of DKD. In this article, we aimed to first establish a novel bioinformatics-based methodology for analyzing the “urinary kidney-specific mRNAs” and verify their potential clinical utility in DKD.

Methods

To select candidate mRNAs, a total of 127 Affymetrix microarray datasets of diabetic kidney tissues and other tissues from humans were compiled and analyzed using an integrative bioinformatics approach. Then, the urinary expression of candidate mRNAs in stage 1 study (n = 82) was verified, and the one with best performance moved on to stage 2 study (n = 80) for validation. To avoid potential detection bias, a one-step Taqman PCR assay was developed for quantification of the interested mRNA in stage 2 study. Lastly, the in situ expression of the selected mRNA was further confirmed using fluorescent in situ hybridization (FISH) assay and bioinformatics analysis.

Results

Our bioinformatics analysis identified sixteen mRNAs as candidates, of which urinary BBOX1 (uBBOX1) levels were significantly upregulated in the urine of patients with DKD. The expression of uBBOX1 was also increased in normoalbuminuric diabetes subjects, while remained unchanged in patients with urinary tract infection or bladder cancer. Besides, uBBOX1 levels correlated with glycemic control, albuminuria and urinary tubular injury marker levels. Similar results were obtained in stage 2 study. FISH assay further demonstrated that BBOX1 mRNA was predominantly located in renal tubular epithelial cells, while its expression in podocytes and urothelium was weak. Further bioinformatics analysis also suggested that tubular BBOX1 mRNA expression was quite stable in various types of kidney diseases.

Conclusions

Our study provided a novel methodology to identify and analyze urinary kidney-specific mRNAs. uBBOX1 might serve as a promising biomarker of DKD. The performance of the selected urinary mRNAs in monitoring disease progression needs further validation.

Electronic supplementary material

The online version of this article (10.1186/s12967-019-1818-2) contains supplementary material, which is available to authorized users.

Analysis of key genes and micro-RNA-mRNA regulatory networks in women with ulcerative interstitial cystitis/pain bladder syndrome

INTRODUCTION AND HYPOTHESIS

This aim of this study was to better understand ulcerative interstitial cystitis/painful bladder syndrome (IC/PBS) at the molecular level and provide new clues related to diagnosis and treatment.

METHODS

The microarray data set GSE11783, including the mRNA and miRNA profiles of bladder tissue obtained at cystoscopic biopsy from patients with ulcerative IC/PBS (presence of at least one Hunner's ulcer) and normal controls, was downloaded from the GEO (Gene Expression Omnibus) database (National Center for Biotechnology Information). These were evaluated using Greenspring GX and Ingenuity Pathway Analysis (IPA) software. The differentially expressed genes (DEGs) and miRNAs (DEMs) in these two groups were identified. Subsequently, the DEGs were subjected to functional analysis, and a protein-protein interaction (PPI) network was constructed. Finally, the miRNA-mRNA regulatory network was visualized using Cystoscope software.

RESULTS

Four DEMs and 1521 DEGs were identified between the ulcerative IC/PBS and control groups. The PPI network of the DEGs was constructed by STRING, which was composed of 393 nodes and 1039 edges, including 221 upregulated genes and 172 downregulated genes. Moreover, 27 genes in the PPI network were identified as hub genes in the IC/PBS group, e.g., PNOC, SSTR1, FPR3, GPR18 and APLNR. Subsequently, 27 clusters were selected from the PPI network using MCODE. It was shown that the most significant cluster consisted of 22 nodes and 231 edges. Moreover, miR-21 was the most significantly upregulated miRNA and was predicted to target one upregulated gene (RASGRP1) and two downregulated genes (KLF5 and SC5D).

CONCLUSIONS

The results of this data mining and integration provide further information on the possible molecular basis of IC/PBS pathogenesis as well as potential biomarkers and therapeutic targets for ulcerative IC/PBS diagnosis and treatment.

Expression of programmed death ligand-1 on bladder tissues is detected in a clinically and histologically well-defined interstitial cystitis cohort

OBJECTIVE

To investigate the expression of programmed death ligand-1 (PD-L1) in interstitial cystitis (IC).

METHODS

We reviewed the data of IC patients underwent hydrodistension plus bladder biopsy. Follow-ups were performed. We assessed the degree of inflammation of the bladder wall on slides stained with hematoxylin and eosin (H&E). We performed immunohistochemistry for PD-L1 expression detection and for counting T lymphocytes and B lymphocytes.

RESULTS

The present study included eight men and 32 women. With H&E staining, we detected 13, 15, and 12 patients with mild, moderate, and severe inflammation. The degree of inflammation was negatively correlated with disease course (P = 0.018) and positively correlated with bladder pain (P < 0.001). Hydrodistension was found effective at postoperative 3-month for 19 patients. Overall, 17, 15, 7, and 1 subject had no, mild, moderate, and high PD-L1 expression, that correlated positively with the degree of inflammation. Compared with patients with no and mild PD-L1 expression, patients with moderate and high PD-L1 expression tended to have more effective hydrodistension outcomes (12 of 32 vs 7 of 8; P = 0.017). In the subset of 12 patients with severe inflammation, there were five of six patients (83.3%) with moderate or high PD-L1 expression and one of six patients (16.7%) with no and mild PD-L1 expression with an effective hydrodistension outcome.

CONCLUSIONS

Expression of PD-L1 on bladder is detected in a cohort of IC patients presented with diffuse global glomerulation or Hunner ulcer. PD-L1 expression is more common in IC patients with severe bladder inflammation.

Acyloxyacyl hydrolase modulates pelvic pain severity

Chronic pelvic pain causes significant patient morbidity and is a challenge to clinicians. Using a murine neurogenic cystitis model that recapitulates key aspects of interstitial cystitis/bladder pain syndrome (IC), we recently showed that pseudorabies virus (PRV) induces severe pelvic allodynia in BALB/c mice relative to C57BL/6 mice. Here, we report that a quantitative trait locus (QTL) analysis of PRV-induced allodynia in F2_CxB progeny identified a polymorphism on chromosome 13, rs6314295 , significantly associated with allodynia (logarithm of odds = 3.11). The nearby gene encoding acyloxyacyl hydrolase ( Aoah) was induced in the sacral spinal cord of PRV-infected mice. AOAH-deficient mice exhibited increased vesicomotor reflex in response to bladder distension, consistent with spontaneous bladder hypersensitivity, and increased pelvic allodynia in neurogenic cystitis and postbacterial chronic pain models. AOAH deficiency resulted in greater bladder pathology and tumor necrosis factor production in PRV neurogenic cystitis, markers of increased bladder mast cell activation. AOAH immunoreactivity was detectable along the bladder-brain axis, including in brain sites previously correlated with human chronic pelvic pain. Finally, AOAH-deficient mice had significantly higher levels of bladder vascular endothelial growth factor, an emerging marker of chronic pelvic pain in humans. These findings indicate that AOAH modulates pelvic pain severity, suggesting that allelic variation in Aoah influences pelvic pain in IC.

Diagnostic value of urinary CXCL10 as a biomarker for predicting Hunner type interstitial cystitis

AIM

To investigate the feasibility of chemokines and cytokines potentially elevated in the bladder tissue of Hunner type interstitial cystitis (HIC) as urinary markers for distinguishing HIC from non-Hunner type interstitial cystitis (NHIC) METHODS: Urine specimens were collected from 41 HIC patients, 25 NHIC patients, and 31 healthy volunteers (control). The supernatants of urine specimens were subjected to ELISA kits for measurements of 10 cytokines and chemokines, whose gene expression was known to be elevated in HIC bladder tissue. Urinary levels normalized by urinary creatinine (Cr) concentration were compared among three groups. Efficiency in differentiating IC and IC subtypes was explored by ROC analysis. The correlation of marker levels with symptom severity, assessed by O'Leary-Sant's symptom index (OSSI) and problem index (OSPI), was examined.

RESULTS

The urinary levels of CXCL10 and NGF were significantly higher in HIC than NHIC. CXCL10 and NGF differentiated HIC against NHIC with AUC of 0.78 and 0.68, respectively. Combination of CXCL10 and NGF levels yielded an AUS of 0.81. The CXCL10 cut-off of 53.2 pg/mg Cr had sensitivity of 46.1%, specificity of 93.7%, positive predictive value of 97.7%, and negative predictive value of 60.0%. The urinary level of other cytokines showed no significant difference between HIC and NHIC. Significant correlation with symptoms was detected for CXCL10 alone.

CONCLUSION

The results suggested that increased urinary level of CXCL10 combined with or without high NGF level could be a promising supplementary biomarker for differentiating HIC from NHIC with modest sensitivity and high specificity.

Expression profile of urothelial transcription factors in bladder biopsies with interstitial cystitis

OBJECTIVES

To characterize interstitial cystitis pathology based on the expression profile of urothelial tissue-specific master transcription factors.

METHODS

Bladder carcinoma cell lines derived from the urothelial stem cells (epithelial or mesenchymal) were used to identify candidate urothelial master transcription factors. Gene expression was measured with quantitative reverse transcription polymerase chain reaction. From the initial screening of 170 transcription factors (human homologs of Drosophila segmentation genes and known master transcription factors from a database), 28 transcription factors were selected. Subsequently, messenger ribonucleic acid from bladder biopsies of interstitial cystitis patients was purified, and gene expression levels of known urothelial marker genes and candidate master transcription factors were measured. Multivariate expression data were analyzed with spss software.

RESULTS

Factor analysis decomposed the expression profile into four axes: principal axis 1 included retinoic acid receptors and 17 candidate master transcription factors. Principal axis 2 included KRT5 and five candidates. Principal axis 3 included transcription factor TP63 and two candidates. Principal axis 4 included SHH and two candidates. Principal component analysis segregated biopsies from Hunner's lesion in the principal component 1 (retinoic acid)/principal component 2 (SOX13)/principal component 3 (TP63) space.

CONCLUSIONS

Urothelial master transcription factors could serve as novel diagnostic markers and potentially explain the molecular pathology of interstitial cystitis.

Sensory Hyperinnervation Distinguishes Bladder Pain Syndrome/Interstitial Cystitis from Overactive Bladder Syndrome

PURPOSE

Pain is the key symptom that distinguishes bladder pain syndrome/interstitial cystitis from overactive bladder syndrome but overlap occurs. To find a discriminating marker for these bladder diseases we examined sensory hyperinnervation and neurotrophin receptor expression in bladder biopsies as well as nerve growth factor levels in urine.

MATERIALS AND METHODS

Bladder biopsies from patients with bladder pain syndrome/interstitial cystitis, including 12 with and 19 without Hunner lesions, 13 with overactive bladder syndrome and 12 healthy controls, were analyzed by immunohistochemistry with antibodies to the nerve cell marker PGP9.5 (neuron-specific protein gene product 9.5), p75^NTR (p75 neurotrophin receptor), the B-lymphocyte marker CD20 and mast cell tryptase. Urinary nerve growth factor was quantified by enzyme-linked immunosorbent assay.

RESULTS

Subepithelial sensory hyperinnervation on PGP9.5 staining had 97% sensitivity and 76% specificity, increased lymphocytic infiltration had 90% sensitivity and 80% specificity, and urothelial defects had 97% sensitivity and 76% specificity to distinguish bladder pain syndrome/interstitial cystitis with and without Hunner lesions from overactive bladder syndrome and healthy controls. Increased sensory innervation was associated with submucosal mast cell localization. Staining of p75^NTR in basal urothelial cells was indicative of bladder pain syndrome/interstitial cystitis. Urinary nerve growth factor levels were below the detection level and did not differentiate bladder diseases from healthy controls.

CONCLUSIONS

Sensory hyperinnervation and basal urothelial p75^NTR staining together with assessment of inflammatory lymphocytes and urothelial integrity allow for the differentiation of bladder pain syndrome/interstitial cystitis and overactive bladder syndrome even in the absence of Hunner lesions. Furthermore, these histopathological criteria enable the identification of early disease stages or oligosymptomatic/asymptomatic cases and may permit timely treatment to prevent disease progress.

Hunner-Type (Classic) Interstitial Cystitis: A Distinct Inflammatory Disorder Characterized by Pancystitis, with Frequent Expansion of Clonal B-Cells and Epithelial Denudation

Interstitial cystitis (IC) is a chronic bladder disease with urinary frequency, bladder discomfort or bladder pain of unknown etiology. Based on cystoscopic findings, patients with IC are classified as either Hunner-type/classic IC (HIC), presenting with a specific Hunner lesion, or non-Hunner-type IC (NHIC), presenting with no Hunner lesion, but post-hydrodistension mucosal bleeding. Inflammatory cell infiltration, composed predominantly of lymphocytes, plasma cells and epithelial denudation, has in the past been documented as a major pathological IC finding. However, the significance of the pathological evaluation of IC, especially with regard to the difference between HIC and NHIC, has been downplayed in recent years. In this study, we performed immunohistochemical quantification of infiltrating T-lymphocytes, B-lymphocytes and plasma cells, and measured the amount of residual epithelium in urinary bladder biopsy specimens taken from patients with HIC and NHIC, and those with no IC, using image analysis software. In addition, in situ hybridization of the light chains was performed to examine clonal B-cell expansion. Lymphoplasmacytic infiltration was significantly more severe in HIC specimens than in NHIC specimens (P <0.0001). Substantial lymphoplasmacytic inflammation (≥200 cells/mm²) was observed in 93% of HIC specimens, whereas only 8% of NHIC specimens were inflamed. Plasmacytic infiltration was more prominent in HIC specimens compared with NHIC and non-IC cystitis specimens (P <0.005). Furthermore, expansion of light-chain-restricted B-cells was observed in 31% of cases of HIC. The amount of residual epithelium was decreased in HIC specimens compared with NHIC specimens and non-IC cystitis specimens (P <0.0001). These results suggest that NHIC and HIC are distinct pathological entities, with the latter characterized by pancystitis, frequent clonal B-cell expansion and epithelial denudation. An abnormality in the B-cell population may be involved in the pathogenesis of HIC.

Hypersensitive bladder: a solution to confused terminology and ignorance concerning interstitial cystitis

Taxonomy or nomenclature concerning interstitial cystitis and its related symptom syndromes is in a state of confusion. After analyzing the reasons for confusion in regard to three components (disease name, symptoms, Hunner's lesion), I would like to propose a new term, "hypersensitive bladder", taking after overactive bladder, as a solution. Hypersensitive bladder symptoms are defined as "increased bladder sensation, usually associated with urinary frequency and nocturia, with or without bladder pain." The proposal of hypersensitive bladder is based on: (i) it does not appear a symptom syndrome, but a disease by ending with an organ name, "bladder"; (ii) it does not contain confusable symptom terms (pain and urgency), but indicates irritative symptoms including pain and urgency; and (iii) it suggests pathophysiological hyperactivity of sensory nerves. Interstitial cystitis is defined by three requirements: (i) hypersensitive bladder symptoms; (ii) bladder pathology; and (iii) no other diseases, where bladder pathology should be clearly stated either as Hunner's lesion or glomerulations after hydrodistention. Hypersensitive bladder can be used for the condition with hypersensitive bladder symptoms, but no obvious disease explaining hypersensitive bladder symptoms identified. Interstitial cystitis is a representative disease causing hypersensitive bladder symptoms, most typically with pain, but might be painless and indistinguishable from overactive bladder. Introducing hypersensitive bladder as a counter concept of overactive bladder into bladder dysfunction taxonomy will facilitate clinical practice and research progress, and attract considerable attention from the medical world.

Are mast cells still good biomarkers for bladder pain syndrome/interstitial cystitis?

PURPOSE

ESSIC identifies mast cell infiltrates of detrusor muscle as a diagnostic criterion for bladder pain syndrome/interstitial cystitis. However, an increased mast cell count is also characteristic of overactive bladder syndrome. The lack of uniformity in mast cell detection methods hampers data comparison. Using state-of-the-art techniques we investigated whether mast cells differ among bladder conditions.

MATERIALS AND METHODS

We analyzed bladder biopsies from 56 patients, including 31 with bladder pain syndrome/interstitial cystitis with (12) or without (19) Hunner lesions, 13 with overactive bladder syndrome and 12 without bladder symptoms to determine the quantity, location, distribution and activation of mast cells using immunohistochemistry with anti-mast cell tryptase. Patients were allocated to study groups by key bladder symptoms commonly used to define conditions (pain and major urgency).

RESULTS

Subepithelial mast cell localization (p <0.001) and an increased detrusor mast cell count (p = 0.029) were characteristic of bladder pain syndrome/interstitial cystitis with Hunner lesions. The optimal cutoff of 32 detrusor mast cells per mm(2) achieved only 68% accuracy with 38% positive predictive value. No difference was observed between bladder pain syndrome/interstitial cystitis without Hunner lesions and overactive bladder syndrome. Patient groups differed in lymphocyte infiltration (p = 0.001), nodular lymphocyte aggregates (p <0.001) and urothelium integrity (p <0.001).

CONCLUSIONS

Subepithelial mast cell distribution was characteristic of bladder pain syndrome/interstitial cystitis with Hunner lesions. Detrusor mastocytosis had poor predictive value for bladder pain syndrome/interstitial cystitis. Mast cell assessment did not distinguish bladder pain syndrome/interstitial cystitis without Hunner lesions from overactive bladder syndrome.

Genes involved in immunity and apoptosis are associated with human presbycusis based on microarray analysis

CONCLUSIONS

Genes involved in immunity and apoptosis were associated with human presbycusis. CCR3 and GILZ played an important role in the pathogenesis of presbycusis, probably through regulating chemokine receptor, T-cell apoptosis, or T-cell activation pathways.

OBJECTIVES

To identify genes associated with human presbycusis and explore the molecular mechanism of presbycusis.

METHODS

Hearing function was tested by pure-tone audiometry. Microarray analysis was performed to identify presbycusis-correlated genes by Illumina Human-6 BeadChip using the peripheral blood samples of subjects. To identify biological process categories and pathways associated with presbycusis-correlated genes, bioinformatics analysis was carried out by Gene Ontology Tree Machine (GOTM) and database for annotation, visualization, and integrated discovery (DAVID). Quantitative RT-PCR (qRT-PCR) was used to validate the microarray data.

RESULTS

Microarray analysis identified 469 up-regulated genes and 323 down-regulated genes. Both the dominant biological processes by Gene Ontology (GO) analysis and the enriched pathways by Kyoto encyclopedia of genes and genomes (KEGG) and BIOCARTA showed that genes involved in immunity and apoptosis were associated with presbycusis. In addition, CCR3, GILZ, CXCL10, and CX3CR1 genes showed consistent difference between groups for both the gene chip and qRT-PCR data. The differences of CCR3 and GILZ between presbycusis patients and controls were statistically significant (p < 0.05).

Correlation of gene expression with bladder capacity in interstitial cystitis/bladder pain syndrome

PURPOSE

Interstitial cystitis and bladder pain syndrome are terms used to describe a heterogeneous chronic pelvic and bladder pain disorder. Despite its significant prevalence, our understanding of disease etiology is poor. We molecularly characterized interstitial cystitis/bladder pain syndrome and determined whether there are clinical factors that correlate with gene expression.

MATERIALS AND METHODS

Bladder biopsies from female subjects with interstitial cystitis/bladder pain syndrome and female controls without signs of the disease were collected and divided into those with normal and low anesthetized bladder capacity, respectively. Samples then underwent RNA extraction and microarray assay. Data generated by these assays were analyzed using Omics Explorer (Qlucore, Lund, Sweden), GeneSifter® Analysis Edition 4.0 and Ingenuity® Pathway Analysis to determine similarity among samples within and between groups, and measure differentially expressed transcripts unique to each phenotype.

RESULTS

A total of 16 subjects were included in study. Principal component analysis and unsupervised hierarchical clustering showed clear separation between gene expression in tissues from subjects with low compared to normal bladder capacity. Gene expression in tissue from patients with interstitial cystitis/bladder pain syndrome who had normal bladder capacity did not significantly differ from that in controls without interstitial cystitis/bladder pain syndrome. Pairwise analysis revealed that pathways related to inflammatory and immune response were most involved.

CONCLUSIONS

Microarray analysis provides insight into the potential pathological condition underlying interstitial cystitis/bladder pain syndrome. This pilot study shows that patients with this disorder who have low compared to normal bladder capacity have significantly different molecular characteristics, which may reflect a difference in disease pathophysiology.

Cytokine expression in patients with bladder pain syndrome/interstitial cystitis ESSIC type 3C

PURPOSE

Bladder wall nitric oxide production in patients with bladder pain syndrome type 3C is increased compared to undetectable nitric oxide in patients with nonHunner bladder pain syndrome and healthy controls. However, the underlying mechanism/s of the increased nitric oxide production is largely unknown. We compared mRNA expression of a select group of cytokines in patients with bladder pain syndrome/interstitial cystitis type 3C and in pain-free controls.

MATERIALS AND METHODS

Cold cup biopsies from 7 patients with bladder pain syndrome type 3C and 6 healthy subjects were analyzed. mRNA expression of IL-4, 6, 10 and 17A, iNOS, TNF-α, TGF-β and IFN-γ was estimated by real-time polymerase chain reaction. IL-17 protein expression was determined by immunohistochemistry. Mast cells were labeled with tryptase to evaluate cell appearance and count.

RESULTS

IL-6, 10 and 17A, and iNOS mRNA levels as well as the number of mast cells infiltrating the bladder mucosa were significantly increased in patients with bladder pain syndrome type 3C compared to healthy controls. TNF-α, TGF-β and IFN-γ mRNA levels were similar in patients and controls. IL-17A expression at the protein level was up-regulated and localized to inflammatory cells and urothelium in patients with bladder pain syndrome type 3C.

CONCLUSIONS

Patients with bladder pain syndrome/interstitial cystitis had increased mRNA levels of IL-17A, 10 and 6, and iNOS. IL-17A might be important in the inflammatory process. To our knowledge the increase in IL-17A is a novel finding that may have new treatment implications.

DNA hybridization efficiency on concave surface nano-structure in hemispherical Janus nanocups

We examined the effect of a concave structure on DNA hybridization efficiency using an inner surface of hemispherical Janus nanocups in the range from 140 to 800 nm. Target DNA was specifically immobilized onto the inner cup surface, hybridized with complementary DNA-attached 20 nm Au probes, and the number of the hybridized probes was counted by scanning electron microscopy. The hybridization density of the attached Au probes on 800 nm nanocups was 255 μm(-2), which was 0.57 times that on a flat surface, 449 μm(-2), and increased to 394 μm(-2) on a 140 nm cup, 0.88 times of a flat surface, as the cup size decreased. The local density of attached Au probes within the central 25% at the bottom of the 800 nm nanocups was 444 μm(-2), which was closer to that on a flat surface, and the tendency was the same for all sizes of cups, indicating that the size dependency of DNA hybridization efficiency on the concave structures were mostly affected by the lower efficiency of side wall hybridization.

Local immune response in bladder pain syndrome/interstitial cystitis ESSIC type 3C

INTRODUCTION AND HYPOTHESIS

Bladder pain syndrome/interstitial cystitis (BPS/IC) is identified based on subjective symptoms which lead to heterogeneous patient populations. Previous studies using gene expression arrays for BPS/IC with Hunner's lesions [European Society for the Study of Interstitial Cystitis (ESSIC) type 3C], a subtype of the condition discernible by cystoscopy, have revealed characteristic immune responses and urothelial abnormalities. This current study aimed to further characterize this subtype using a gene expression panel. We hypothesized that B-cell activation with high levels of urinary antibody concentration would be found.

METHODS

Cold-cup bladder biopsies, catheterized urine and blood were collected from 15 BPS/IC ESSIC type 3C patients, 11 non-inflammatory overactive bladder (OAB) patients and eight healthy controls. Gene expression in biopsies was quantified by real-time quantitative polymerase chain reaction (RT-qPCR), immunohistochemistry was performed on bladder tissue and urinary immunoglobulins G and A were quantified by enzyme-linked immunosorbent assay. Statistical analyses included the Kruskal-Wallis test for non-parametric data and post hoc tests identified differences between groups.

RESULTS

High expression of T- and B-cell markers (CTLA4, CD20, CD79A, IGH@), low expression of urothelial markers (KRT20, UPK1B, UPK3A), focal lymphoid aggregates in the submucosa and high immunoglobulin concentration in urine were found exclusively in BPS/IC ESSIC type 3C patients. Results for OAB were in intermediate ranges between the other two groups and UPK1B even reached significantly lower expression when compared to healthy controls.

CONCLUSIONS

BPS/IC ESSIC type 3C is characterized by a local adaptive immune response with elevated urinary antibody concentrations. Quantification of urinary immunoglobulin levels could be used for a non-invasive diagnosis of BPS/IC ESSIC type 3C.

Interstitial cystitis/bladder pain syndrome: diagnosis and management

INTRODUCTION AND HYPOTHESIS

The bladder pain syndrome (BPS) is a spectrum of urological symptoms characterised by bladder pain with typical cystoscopic features. Diagnosis and management of this syndrome may be difficult. There is no evidence-based management approach for the diagnosis or treatment of BPS. The objective of this study was to critically review and summarise the evidence relating to the diagnosis and treatment of the bladder pain syndrome.

METHODS

A review of published data on the diagnosis and treatment of the BPS was performed. Our search was limited to English-language articles, on the "diagnosis", and "management" or "treatment" of "interstitial cystitis" and the "bladder pain syndrome" in "humans."

RESULTS

Frequency, urgency and pain on bladder filling are the most common symptoms of BPS. All urodynamic volumes are reduced in patients with BPS. Associated conditions include psychological distress, depression, history of sexual assault, irritable bowel syndrome and fibromyalgia. Cystoscopy remains the test for definitive diagnosis, with visualisation of haemorrhage on cystoreduction. A multidisciplinary treatment approach is essential in the management of this condition. Orally administered amitriptyline is an efficacious medical treatment for BPS. Intravesical hyaluronic acid and local anaesthetic, with/without hydrodistension are among new treatment strategies. Sacral or pudendal neuromodulation is effective, minimally invasive and safe. Surgery is reserved for refractory cases.

CONCLUSIONS

There remains a paucity of evidence for the diagnosis and treatment of BPS. We encountered significant heterogeneity in the assessment of symptoms, duration of treatment and follow up of patients in our literature review.

'Omics' approaches to understanding interstitial cystitis/painful bladder syndrome/bladder pain syndrome

Recent efforts in the generation of large genomics, transcriptomics, proteomics, metabolomics and other types of 'omics' data sets have provided an unprecedentedly detailed view of certain diseases, however to date most of this literature has been focused on malignancy and other lethal pathological conditions. Very little intensive work on global profiles has been performed to understand the molecular mechanism of interstitial cystitis/painful bladder syndrome/bladder pain syndrome (IC/PBS/BPS), a chronic lower urinary tract disorder characterized by pelvic pain, urinary urgency and frequency, which can lead to long lasting adverse effects on quality of life. A lack of understanding of molecular mechanism has been a challenge and dilemma for diagnosis and treatment, and has also led to a delay in basic and translational research focused on biomarker and drug discovery, clinical therapy, and preventive strategies against IC/PBS/BPS. This review describes the current state of 'omics' studies and available data sets relevant to IC/PBS/BPS, and presents opportunities for new research directed at understanding the pathogenesis of this complex condition.

MCP-1-induced histamine release from mast cells is associated with development of interstitial cystitis/bladder pain syndrome in rat models

OBJECTIVE

Interstitial cystitis/bladder pain syndrome (IC/BPS) is characterized by overexpression of monocyte chemoattractant protein-1 (MCP-1) in bladder tissues and induction of mast cell (MC) degranulation. This study was undertaken to explore the mechanism of action of MCP-1 in the development of IC/BPS.

METHODS

A rat model of IC/BPS was developed by perfusing bladders of nine SPF- grade female Sprague-Dawley rats with protamine sulfate and lipopolysaccharide (PS+LPS). MCP-1 and histamine levels in bladder tissue and urine were detected by immunohistochemistry and ELISA. MC degranulation was measured by immunofluorescence techniques and chemokine (C-C motif) receptor 2 (CCR2) was assayed by flow cytometry.

RESULTS

Increased MCP-1 expression in bladder tissue and elevated MCP-1 and histamine levels were observed in the urine of LS+LPS-treated rats. This was accompanied by the expression of CCR2 on MC surfaces, suggesting MCP-1 may induce MC degranulation through CCR2. Exposure to LPS stimulated MCP-1 expression in bladder epithelial cells, and exposure to MCP-1 induced histamine release from MCs.

CONCLUSIONS

MCP-1 upregulation in IC/BPS is one of possible contributing factors inducing histamine release from MCs. CCR2 is involved in the process of mast cell degranulation in bladder tissues. These changes may contribute to the development of symptoms of IC/BPS.

[Experimental studies on microcirculatory inflammatory reactions of the urinary bladder]

BACKGROUND

The vascular endothelium is a primary target of ischemia/reperfusion (IR) injury of the urinary bladder. In case of interstitial cystitis (painful bladder syndrome) or in cyclophosphamide-induced hemorrhagic cystitis, the injury is initiated at the epithelial/urothelial surface and propagates towards the interstitium, causing secondary involvement of the microvasculature. Hence the aim of our study was to assess and compare the microcirculatory aspects of the non-infectious forms of cystitis with that of IR-caused reactions.

MATERIALS AND METHODS

In male Sprague-Dawley rats, interstitial cystitis was induced by intravesical instillation of protamine sulphate (2 mg in 200 μl saline for 30 min; n = 6). In another group, cyclophosphamide (75 mg/kg, ip) was administered 24 hr prior to the experiments (n = 5). In the third group, urinary bladder ischemia was induced by 60-min occlusion of the vessels supplying the bladder (n = 5). The microcirculatory inflammatory reactions were investigated by fluorescence intravital microscopy 60 min after reperfusion and 24 hr after protamine sulphate instillation or cyclophosphamide administration, respectively. In the control group, the bladder was instilled with saline (n = 5).

RESULTS

Rolling of leukocytes increased ~3-fold in the postcapillary vessels in the protamine sulphate-treated group and the increase in this parameter was ~5 and ~6.5-fold in cyclophosphamide and IR groups, respectively. The increase in leukocyte adherence reached similar, approx. 7-fold increase in each of the challenged groups. The red blood cell velocity in the capillaries decreased in the protamine sulphate and IR groups, while the velocity increased moderately in the cyclophosphamide-treated group.

CONCLUSIONS

Our results demonstrate that direct endothelial injury (caused by IR), as well as protamine sulphate and cyclophosphamide administrations induce inflammatory microcirculatory changes of the urinary bladder. These observations suggest a causative role for microcirculatory disturbances in the pathogenesis of interstitial cystitis and hemorrhagic cystitis as well.

Integration analysis of quantitative proteomics and transcriptomics data identifies potential targets of frizzled-8 protein-related antiproliferative factor in vivo

What's known on the subject? and What does the study add? Interstitial cystitis (IC) is a prevalent and debilitating pelvic disorder generally accompanied by chronic pain combined with chronic urinating problems. Over one million Americans are affected, especially middle-aged women. However, its aetiology or mechanism remains unclear. No efficient drug has been provided to patients. Several urinary biomarker candidates have been identified for IC; among the most promising is antiproliferative factor (APF), whose biological activity is detectable in urine specimens from >94% of patients with both ulcerative and non-ulcerative IC. The present study identified several important mediators of the effect of APF on bladder cell physiology, suggesting several candidate drug targets against IC. In an attempt to identify potential proteins and genes regulated by APF in vivo, and to possibly expand the APF-regulated network identified by stable isotope labelling by amino acids in cell culture (SILAC), we performed an integration analysis of our own SILAC data and the microarray data of Gamper et al. (2009) BMC Genomics 10: 199. Notably, two of the proteins (i.e. MAPKSP1 and GSPT1) that are down-regulated by APF are involved in the activation of mTORC1, suggesting that the mammalian target of rapamycin (mTOR) pathway is potentially a critical pathway regulated by APF in vivo. Several components of the mTOR pathway are currently being studied as potential therapeutic targets in other diseases. Our analysis suggests that this pathway might also be relevant in the design of diagnostic tools and medications targeting IC.

OBJECTIVE

• To enhance our understanding of the interstitial cystitis urine biomarker antiproliferative factor (APF), as well as interstitial cystitis biology more generally at the systems level, we reanalyzed recently published large-scale quantitative proteomics and in vivo transcriptomics data sets using an integration analysis tool that we have developed.

MATERIALS AND METHODS

• To identify more differentially expressed genes with a lower false discovery rate from a previously published microarray data set, an integrative hypothesis-testing statistical approach was applied. • For validation experiments, expression and phosphorylation levels of select proteins were evaluated by western blotting.

RESULTS

• Integration analysis of this transcriptomics data set with our own quantitative proteomics data set identified 10 genes that are potentially regulated by APF in vivo from 4140 differentially expressed genes identified with a false discovery rate of 1%. • Of these, five (i.e. JUP, MAPKSP1, GSPT1, PTGS2/COX-2 and XPOT) were found to be prominent after network modelling of the common genes identified in the proteomics and microarray studies. • This molecular signature reflects the biological processes of cell adhesion, cell proliferation and inflammation, which is consistent with the known physiological effects of APF. • Lastly, we found the mammalian target of rapamycin pathway was down-regulated in response to APF.

CONCLUSION

• This unbiased integration analysis of in vitro quantitative proteomics data with in vivo quantitative transcriptomics data led to the identification of potential downstream mediators of the APF signal transduction pathway.

Urinary chemokines as noninvasive predictors of ulcerative interstitial cystitis

PURPOSE

Based on basic research findings an increase in chemokines and cytokines (CXCL-1 and 10, nerve growth factor and interleukin-6) is considered responsible for inflammation and afferent sensitization. In this cross-sectional study we tested the hypothesis that select chemokines are increased in the urine of patients with ulcerative and nonulcerative interstitial cystitis/painful bladder syndrome.

MATERIALS AND METHODS

Midstream urinary specimens were collected from 10 patients with ulcerative and nonulcerative interstitial cystitis/painful bladder syndrome, respectively, and from 10 asymptomatic controls. Urinary levels of 7 cytokines were measured by a human cytokine/chemokine assay. Nerve growth factor was measured by enzyme-linked immunosorbent assay.

RESULTS

Urinary levels of most chemokines/cytokines were tenfold to 100-fold lower in asymptomatic controls vs patients with ulcerative and nonulcerative interstitial cystitis/painful bladder syndrome. Univariate comparison of 8 tested proteins in the ulcerative vs nonulcerative groups revealed a significant fivefold to twentyfold increase in CXCL-10 and 1, interleukin-6 and nerve growth factor (ANOVA p<0.001).

CONCLUSIONS

Differential expression of chemokines in ulcerative and nonulcerative subtypes of interstitial cystitis/painful bladder syndrome suggests differences in paracrine signaling between the 2 entities.